code: def resolve_request_headers(request_headers=None):
      """Generate a set of request headers from registered providers. Request headers are resolved in
      the order that providers are registered. Argument headers are applied last.
  
      This function iterates through all request header providers in the registry. Additional context
      providers can be registered as described in
      :py:class:`mlflow.tracking.request_header.RequestHeaderProvider`.
  
      :param tags: A dictionary of request headers to override. If specified, headers passed in this
          argument will override those inferred from the context.
      :return: A dictionary of resolved headers.
      """
  
      all_request_headers = {}
      for provider in _request_header_provider_registry:
          try:
              if provider.in_context():
                  # all_request_headers.update(provider.request_headers())
                  for (
                      header,
                      value,
                  ) in provider.request_headers().items():
                      all_request_headers[header] = (
                          f"{all_request_headers[header]} {value}"
                          if header in all_request_headers
                          else value
                      )
          except Exception as e:
              _logger.warning(
                  "Encountered unexpected error during resolving request headers: %s",
                  e,
              )
  
      if request_headers is not None:
          all_request_headers.update(request_headers)
  
      return all_request_headers
  
file_path: mlflow/mlflow/tracking/request_header/registry.py
imports: import logging
  import warnings
  import entrypoints
  from mlflow.tracking.request_header.databricks_request_header_provider import DatabricksRequestHeaderProvider
  from mlflow.tracking.request_header.default_request_header_provider import DefaultRequestHeaderProvider
label_desc: Use image node_id 1 for calling a global function with example usage: resolve_request_headers(request_headers) and returns: all_request_headers